Updated. So now we know why Ustream has been busy raising new funding from Korea Telecom and existing investors DCM and Softbank, and possibly why former CEO John Ham recently stepped down: The company collected less than half of the $75 million funding round it announced in early 2010, according to an SEC filing released Friday. [Hat tip to Business Insider.]

A quick recap: Last February, Ustream raised a strategic funding round led by Japanese mobile phone and Internet operator Softbank that altogether was worth up to $75 million. Softbank put in $20 million in an initial investment, taking a 13.7 percent stake in Ustream that valued the company at around $150 million. Softbank had 18 months to invest up to $55 million more, which would have given it a majority stake in the live streaming company.

But those funds never came.

The SEC filing indicates Ustream brought in about $33 million of the $75 million that it hoped to raise from Softbank, and Softbank never took a controlling stake in the firm. Instead, the startup announced a $10 million investment from Korea Telecom and an agreement to launch Ustream Korea as part of its Ustream Asia joint venture. Later, DCM and Softbank put another $6 million into Ustream and former CEO Ham stepped down.

Assuming the Korea Telecom and following DCM/Softbank investments are separate from Ustream’s $33 million Series B round, the company has raised a total of about $62 million. That’s not too shabby, but it’s far from the “more than $100 million” that continues to be quoted as Ustream’s total funding raised to date. It also answers the question of why Ustream needed to raise more cash just a year after the Softbank funding was announced: It didn’t burn through $75 million; it just never received the bulk of those funds.

The SEC filing also indicates a softening of Softbank’s strategic interest in Ustream. After all, rather than invest another $55 million of its own cash to take control of the live streaming startup, Softbank pursued a strategy of bringing in an additional shareholder to fund expansion instead. So what does Softbank know that we don’t?

Ustream did not respond to a request for comment by the time of this writing. We’ll update if we hear back from the company.

Update: Ustream CEO Brad Hunstable confirmed that its total funding to date is about $62 million, and gave some more background on the funding plans. He said that the primary reason for bringing on Korea Telecom was to have a strategic local partner on board, in the same way that Softbank is providing local support in Japan.

“We have the capital we need,” Hunstable said. As for its relationship with Softbank and the joint venture around Ustream Japan: “We continue to have big plans for Ustream Japan… It’s taking off and continues to grow month-over-month.”